The GRID – Hype or Reality?

Roger BarlowManchester and Stanford University

Symposium in celebration of John Vincent Atanasoff Iowa State University, 31st October

2003

What is the Grid?Problems and Tools that solve themProgressProspects

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What is the GRID? 1: The Press

The new Grid computing technologies are set to revolutionise the way scientists use the world’s computing resources.

The technology now being deployed for particle physics will ultimately change the way that science and business are undertaken in the years to come. This will have a profound effect on the way society uses information technology, much as the World Wide Web did.

Grid technology will extend to fields like bioinformatics, digital archive and biodiversity informatics. “We are very excited to be able to

participate in such a revolutionary global collaboration.”

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What is the GRID? 2: For Politicians

Computing coming out of a wall socket

Power:

110V AC

60Hz

Computing: ?

?

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What is the GRID? 3: For Machine vendors

Another name for a CPU cluster

A very limited and unimaginative use. But it sells boxes!

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What is the GRID? Here is a (transport) grid that works

Get from anywhere* to anywhere* (home, school, office, theater, park, mall..)

By any* means (car, truck, bus…)

For any* purpose (work, pleasure,shopping…) A user’s activities vary.

* within reasonable limits

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Aside: What is the WEB? Computers talk to computersThey say:”Give me that file.”

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What is the GRID? Computers talk to computers

They say anything

Find data like this…

Add this data to that data

Run this program on those data

Collect results and plot them

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600+ physicists

9 countries

71 institutes

Moving from a CENTRALISED

To a

DISPERSED

Computing model

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Particle Physics and building the Grid

The Grid needs Particle Physics as trail-blazers…

• Demanding users with demanding problems

• Amateurs: Knowledgeable but non expert

• Write their own programs. Badly.

• Lots of resources – different universities/countries

• COTS components - heterogeneous

• Software not mission-critical

Particle Physics needs the Grid…

Locate data – which may be in different sites

Select events and process (take-the-job-to-the-data

beats take-the-data-to-the-job)

Collate results

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Warning: Cyberspace is dangerous!

Rogues and vagabonds: evil people and stupid people

How can you trust anyone? How can anyone trust you?

How can we build a grid when all the doors and gates locked?

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Old Solution: Passwords• Not really secure• Multiple passwords are a

pain for users• Does not scale for millions

of users (N) , tens of thousands of sites (M)

SYSTEM

Gatekeeper

Gate

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Eureka! RSA Encryption

12317 | 3233

123855

8552753 | 3233

(123+5)*2123

(256-10)*0.5256

PUBLIC key (3233,17)

PRIVATE key (3233,2753)

Rivest, Shamir, Adleman

Can deduce private key from public key in principle but not in practice

3233=53*61

52*60= (2753*17-1)*15

Anyone can do this using public keyOnly holder of private key can do

this

Trivial Example

Simple Example

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What you can do with it

• Suppose I trust Charles Adams• Charles Adams has his own private key• I have his public key (so do lots of people)• If I get a coded message that makes sense

when I decode it, I know CA must have written it• If you bring me such a message saying ‘This

guy is John Doe of Iowa State…’ then I believe it because I believe CA.

• This is a CERTIFICATE. Your certificate. ‘Signed’ by CA

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Authentication Solved

• There are several (not many) Certificate Authorities (DOE, UK, France, Germany…)

• Each CA should have a rigorous procedure for issuing certificates, generally involving personal contact though maybe multilevel

• A site chooses which it will recognise, on the basis of trustworthiness

• When I approach a site with my certificate, they know I am who I say I am

• ~N+M transactions

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Next Hurdle: Authorisation

• Your ID gets you into the bar – but it doesn’t buy you a beer

• ‘Virtual Organisation’ – membership allows you to use resources

• People join a VO. Or several VOs (N transactions)

• Sites give resources to VO (M transactions)

• ‘Generic accounts’ make it easy

“Please present your ticket and photo ID…”

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The BaBar VO

Want to join?Just put your

certificate name into a file .cert-id on your SLAC BaBar account

cron jobs do the rest

Simple AND secure

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Sandboxes• You ship a whole load of files

to the remote site. (May include the executable.)

• It runs and generates bytes to gigabytes of output files

• You get all these back

Your job operates only within the input and output sandboxes, not in the rest of the remote system. So everyone is safe

Issues:• How do you know which files to send?• How much can you assume standard libraries

etc are present? (“As little as possible” is the right answer.)

• How do the files come back? Pull (inconvenience) or push (risky).

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AFS solves all our sandbox problems

Run/test jobs locally in directory which is part of afs cell: /afs/<mysite>/<user>/<dirname>

Files needed are in this directory or linked from it (except for the big raw data files.)

Output files created in this directory

At start of remote job, klog to /afs/<mysite>/<user>/<dirname>All the I/O (except raw data input) is done

thereUses gsiklog (certificate gives token).

Transportable

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Stuff that would be nice

• Resource Brokering• Job monitoring• Fun to use GUI interfaces• SRB for storage

• But we don’t want to hang around till it’s ready. Well, I don’t.

(and 50% of software projects fail)

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BaBarGrid(Sorry, no demo today. Just screenshots)

Some machines already in the system

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Start by finding some dataUse experiment-specific jargon to specify what sort of data you want

Say where you want to run (Here MAN and RAL)

Get whole bunch of input files

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One command runs the jobsManchester

Rutherford Lab

’job’ is standard user (badly) written analysis code: nothing special required

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And get the answer

Plot obtained by merging all the job outputs from all the sites

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Coming Next: the LHC

• Large Hadron Collider – CERN. 14 TeV proton-proton collisions

• 4 Experiments – each an order of magnitude bigger than BaBar

• Massive data analysis requirements• Switch on 2007• Grid computing built in from the

start

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LCG now rolling out

First LHC Computing Grid – ~4,000 CPUs

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The Grid

• It’s real – despite the hype• Being test-driven by Particle

Physicists– Especially in Europe

• You will be using it sooner or later – opening possibilities you never thought possible

• Get your certificate and join the fun